It is common practice among drivers of over-the-road equipment, such as trucks, buses, tractors, R.V. equipment, and the like (referred to herein as "trucks"), to assist drivers behind them to pass their vehicles. They do this by flashing their headlights, and this means that the high beams of the headlights are intermittently operated or flashed to indicate an "all-clear" to the passing driver. Truch high beams are so powerful that they can temporarily blind the passing driver, through reflection in his mirrors, or drivers approaching the passed truck on the opposite side of the road. Thus, what is intended to promote safety in passing can actually become a hazard if the flashing high beams interfere with the vision of another driver.